Biology: Cell Structure and Genetics

Cell Structure and Function

• Cell Theory: All living organisms are composed of cells; the cell is the basic unit of life; all cells arise from pre-existing cells.
• Prokaryotic vs. Eukaryotic Cells:
  • Prokaryotic: No nucleus, smaller, simpler (e.g., bacteria).
  • Eukaryotic: Nucleus present, larger, more complex (e.g., plant and animal cells).
• Organelles:
  • Nucleus: Contains genetic material (DNA).
  • Mitochondria: Powerhouse of the cell, site of ATP production.
  • Ribosomes: Protein synthesis.
  • Endoplasmic Reticulum: Rough (with ribosomes) for protein synthesis; Smooth for lipid synthesis.
  • Golgi Apparatus: Modifies, sorts, and packages proteins.
  • Lysosomes: Digestion and waste removal.

Genetics

• DNA Structure: Double helix, nucleotides (adenine, thymine, cytosine, guanine).
• Gene: Segment of DNA that codes for a protein.
• Mendelian Genetics:
  • Law of Segregation: Alleles segregate during gamete formation.
  • Law of Independent Assortment: Genes for different traits segregate independently.
• Punnett Squares: Tool for predicting genotypic and phenotypic ratios.

Evolution

• Theory of Natural Selection: Survival of the fittest; organisms with advantageous traits reproduce more successfully.
• Speciation: Process by which new species arise.
• Fossil Record: Provides evidence of change over time.
• Common Ancestry: All life shares a common ancestor.

Ecology

• Ecosystems: Interactions between living organisms and their environment.
• Biomes: Large geographical areas with distinct climates and ecosystems (e.g., deserts, forests).
• Food Chain/Web: Shows energy flow; producers (plants) → consumers (herbivores, carnivores) → decomposers.
• Population Dynamics: Study of how populations change over time and space.

Human Biology

• Organ Systems:
  • Circulatory: Transports blood, nutrients, gases.
  • Respiratory: Facilitates gas exchange (oxygen and carbon dioxide).
  • Digestive: Breaks down food, absorbs nutrients.
  • Nervous: Controls body functions, processes information.
• Homeostasis: Maintaining stable internal conditions despite external changes.

Plant Biology

• Photosynthesis: Process by which plants convert light energy into chemical energy (glucose).
• Plant Structure:
  • Roots: Absorb water and nutrients.
  • Stems: Support and transport.
  • Leaves: Main site of photosynthesis.
• Reproduction: Asexual (via runners, tubers) and sexual (pollination, seeds).

Microbiology

• Types of Microorganisms:
  • Bacteria: Prokaryotic, diverse, some pathogenic.
  • Viruses: Non-living, require a host to replicate.
  • Fungi: Eukaryotic, decomposers, some pathogenic.
• Role in Ecosystems: Nutrient cycling, decomposition, symbiosis.

Biotechnology

• Genetic Engineering: Manipulating DNA for desired traits (e.g., GMO crops).
• CRISPR: Technique for editing genes.
• Bioremediation: Use of microbes to clean up environmental contaminants.

Cell Structure and Function

• Cell Theory: Fundamental principles defining that all living things are made of cells, which are the basic life units, and cells arise from existing cells.
• Prokaryotic Cells: Characterized by no nucleus, smaller size, and simpler structure, typical examples include bacteria.
• Eukaryotic Cells: Feature a defined nucleus, larger and more complex than prokaryotic cells, including plant and animal cells.
• Nucleus: Houses genetic material (DNA) and controls cellular activities.
• Mitochondria: Known as the powerhouse of the cell, where ATP (energy) production occurs.
• Ribosomes: Sites of protein synthesis, found freely in the cytoplasm or attached to the endoplasmic reticulum.
• Endoplasmic Reticulum (ER): Divided into rough ER (with ribosomes for protein synthesis) and smooth ER (involved in lipid synthesis).
• Golgi Apparatus: Responsible for modifying, sorting, and packaging proteins for secretion or use within the cell.
• Lysosomes: Contains digestive enzymes to break down waste materials and cellular debris.

Genetics

• DNA Structure: Composed of a double helix formed by nucleotides, including adenine (A), thymine (T), cytosine (C), and guanine (G).
• Gene Definition: A specific segment of DNA that encodes for a particular protein.
• Mendelian Genetics:
  • Law of Segregation: Each allele segregates into separate gametes during their formation.
  • Law of Independent Assortment: Inheritance of one trait is independent of another trait's inheritance.
• Punnett Squares: A graphical tool used to predict the probability of genotypic and phenotypic outcomes of genetic crosses.

Evolution

• Natural Selection: The process where organisms with advantageous traits are more likely to survive and reproduce, often summarized as "survival of the fittest."
• Speciation: The evolutionary process through which new species arise, often due to environmental factors and reproductive isolation.
• Fossil Record: A historical archive that provides evidence of biological evolution and changes over time.
• Common Ancestry: The concept that all life on Earth shares a common ancestor, emphasizing genetic links among diverse organisms.

Ecology

• Ecosystems: Defined by the interactions among organisms and their physical environment, encompassing living and non-living components.
• Biomes: Large ecological areas on Earth with distinct climatic conditions and life forms, such as deserts and forests.
• Food Chain/Web: Illustrates the flow of energy through an ecosystem, starring producers (plants) followed by consumers (herbivores, carnivores) and decomposers.
• Population Dynamics: Examines how and why populations change in size, distribution, and composition over time.

Human Biology

• Organ Systems:
  • Circulatory System: Responsible for the movement of blood, nutrients, and gases throughout the body.
  • Respiratory System: Enables gas exchange, primarily oxygen intake and carbon dioxide expulsion.
  • Digestive System: Breaks down food to absorb essential nutrients into the bloodstream.
  • Nervous System: Controls body functions and processes sensory information for responsiveness.
• Homeostasis: The ability of an organism to maintain stable internal conditions regardless of external environmental changes.

Plant Biology

• Photosynthesis: The biochemical process through which plants convert solar energy into chemical energy stored in glucose.
• Plant Structure:
  • Roots: Facilitate water and nutrient absorption from the soil.
  • Stems: Provide structural support and transport nutrients and water.
  • Leaves: The primary site for photosynthesis, where gas exchange occurs.
• Reproductive Strategies: Includes asexual reproduction (via runners or tubers) and sexual reproduction (pollination leading to seed production).

Microbiology

• Types of Microorganisms:
  • Bacteria: Diverse group of prokaryotic organisms, some of which can cause diseases.
  • Viruses: Non-living infectious agents that require host cells for replication.
  • Fungi: Eukaryotic decomposers, playing a key role in nutrient recycling; some are pathogenic.
• Ecological Role: Microorganisms contribute to nutrient cycling, decomposing organic matter, and establishing symbiotic relationships with other organisms.

Biotechnology

• Genetic Engineering: The manipulation of organisms' DNA to express desired traits, commonly seen in genetically modified organisms (GMOs).
• CRISPR: An advanced gene-editing technology that enables precise modifications of DNA sequences in living organisms.
• Bioremediation: The process involving the use of microbes to clean up contaminated environments, such as oil spills or heavy metal pollution.

This quiz covers essential concepts of cell structure, including cell theory, organelles, and the differences between prokaryotic and eukaryotic cells. It also delves into the fundamentals of genetics, such as DNA structure and Mendelian genetics. Test your knowledge on these crucial biological topics!